System and method of reducing interruptions for vehicle to vehicle communication

ABSTRACT

An apparatus and method are provided for transmitting signals in a vehicle to vehicle (V2V)/vehicle to everything (V2X) communication system. The method includes receiving a handover command message from a base station, the handover command message comprising information on a first resource pool, selecting a resource for transmitting data from a second resource pool without sensing the second resource pool, if the handover command message further comprises information on the second resource pool, and transmitting the data based on the resource for transmitting data from the second resource pool.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation application of prior application Ser.No. 15/627,953, filed on Jun. 20, 2017, which was based on and claimedpriority under 35 U.S.C § 119(e) of a U.S. Provisional application Ser.No. 62/352,772, filed on Jun. 21, 2016, in the U.S. Patent and TrademarkOffice, the disclosure of which is incorporated by reference herein inits entirety.

TECHNICAL FIELD

The present disclosure relates to a device to device (D2D) communicationsystem. More particularly, the present disclosure relates to vehicle tovehicle (V2V) or vehicle to everything (V2X) communication system and amethod for transmission and reception.

BACKGROUND

To meet the demand for wireless data traffic having increased sincedeployment of 4^(th) generation (4G) communication systems, efforts havebeen made to develop an improved 5^(th) generation (5G) or pre-5Gcommunication system. Therefore, the 5G or pre-5G communication systemis also called a ‘Beyond 4G Network’ or a ‘Post long term evolution(LTE) System’. The 5G communication system is considered to beimplemented in higher frequency (mm Wave) bands, e.g. 60 GHz bands, soas to accomplish higher data rates. To decrease propagation loss of theradio waves and increase the transmission distance, the beamforming,massive multiple-input multiple-output (MIMO), full dimensional MIMO(FD-MIMO), array antenna, an analog beam forming, large scale antennatechniques are discussed in 5G communication systems. In addition, in 5Gcommunication systems, development for system network improvement isunder way based on advanced small cells, cloud radio access networks(RANs), ultra-dense networks, device-to-device (D2D) communication,wireless backhaul, moving network, cooperative communication,coordinated multi-points (CoMP), reception-end interference cancellationand the like. In the 5G system, hybrid frequency shift keying (FSK) andquadrature amplitude modulation (QAM) modulation (FQAM) and slidingwindow superposition coding (SWSC) as an advanced coding modulation(ACM), and filter bank multi carrier (FBMC), non-orthogonal multipleaccess (NOMA), and sparse code multiple access (SCMA) as an advancedaccess technology have been developed.

The Internet, which is a human centered connectivity network wherehumans generate and consume information, is now evolving to the internetof things (IoT) where distributed entities, such as things, exchange andprocess information without human intervention. The internet ofeverything (IoE), which is a combination of the IoT technology and thebig data processing technology through connection with a cloud server,has emerged. As technology elements, such as “sensing technology”,“wired/wireless communication and network infrastructure”, “serviceinterface technology”, and “Security technology” have been demanded forIoT implementation, a sensor network, a machine-to-machine (M2M)communication, machine type communication (MTC), D2D communication, andso forth have been recently researched. Such an IoT environment mayprovide intelligent Internet technology services that create a new valueto human life by collecting and analyzing data generated among connectedthings. IoT may be applied to a variety of fields including smart home,smart building, smart city, smart car or connected cars, smart grid,health care, smart appliances and advanced medical services throughconvergence and combination between existing information technology (IT)and various industrial applications.

In line with this, various attempts have been made to apply 5Gcommunication systems to IoT networks. For example, technologies such asa sensor network, MTC, and M2M communication, D2D communication, may beimplemented by beamforming, MIMO, and array antennas. Application of acloud RAN as the above-described Big Data processing technology may alsobe considered to be as an example of convergence between the 5Gtechnology and the IoT technology.

D2D communication enables data communication services between the userequipment (UE). During the D2D communication (also referred as sidelink(SL) communication) a transmitting UE can transmit data packets to agroup of UEs or broadcast data packets to all the UEs or send unicastdata packets to a specific UE. Recently 3rd generation partnershipproject (3GPP) standard group has initiated work item to enhance the SLcommunication mechanism for vehicle to vehicle (V2V) or vehicle toeverything (V2X) communication. One of the enhancements proposed forefficient transmission is to perform sensing for UE autonomous resourceselection. According to present procedure, data transmission can bedelayed significantly. Therefore, a need exists for reducinginterruptions in data transmission using sensing for UE autonomousresource selection.

The above information is presented as background information only toassist with an understanding of the present disclosure. No determinationhas been made, and no assertion is made, as to whether any of the abovemight be applicable as prior art with regard to the present disclosure.

SUMMARY

Aspects of the present disclosure are to address at least theabove-mentioned problems and/or disadvantages and to provide at leastthe advantages described below. Accordingly, an aspect of the presentdisclosure is to provide a method and apparatus for reducinginterruptions in vehicle to vehicle (V2V) transmission using sensing onresource pool for UE autonomous resource selection, thereby improvingthe system performance.

In accordance with an aspect of the present disclosure, a method fortransmitting data of a user equipment (UE) is provided. The methodincludes receiving a handover command message from a base station, thehandover command message comprising information on a first resourcepool, selecting a resource for transmitting data from a second resourcepool without sensing the second resource pool, if the handover commandmessage further comprises information on the second resource pool, andtransmitting the data based on the resource for transmitting data fromthe second resource pool.

In accordance with another aspect of the present disclosure, a methodfor transmitting information of a base station is provided. The methodincludes receiving information on at least one resource pool fromanother base station, and transmitting a handover command messagecomprising information on a first resource pool and information on asecond resource pool based on the information on the at least oneresource pool.

In accordance with another aspect of the present disclosure, a UE fortransmitting data is provided. The UE includes a transceiver to transmitand receive signals, and at least one processor configured to control toreceive a handover command message from a base station, the handovercommand message comprising information on a first resource pool, selecta resource for transmitting data from a second resource pool withoutsensing the second resource pool, if the handover command messagefurther comprises information on the second resource pool, and transmitthe data based on the resource for transmitting data from the secondresource pool.

In accordance with another aspect of the present disclosure, a basestation for transmitting information is provided. The base stationincludes a transceiver to transmit and receive signals, and at least oneprocessor configured to control to receive information on at least oneresource pool from another base station and transmit a handover commandmessage comprising information on a first resource pool and informationon a second resource pool based on the information on the at least oneresource pool.

Other aspects, advantages, and salient features of the disclosure willbecome apparent to those skilled in the art from the following detaileddescription, which, taken in conjunction with the annexed drawings,discloses various embodiments of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certainembodiments of the present disclosure will be more apparent from thefollowing description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 illustrates the timeline for user equipment (UE) autonomousresource selection for vehicle to vehicle (V2V) communication accordingto an embodiment of the present disclosure;

FIG. 2 illustrates the signaling flow according to the scenario 1according to an embodiment of the present disclosure;

FIG. 3 illustrates an interruption of at least 1 s due to the sensingaccording to scenario 1 according to an embodiment of the presentdisclosure;

FIG. 4 illustrated the first embodiment for scenario 1 according to anembodiment of the present disclosure;

FIG. 5 is a flowchart illustrating the first embodiment of scenario 1according to an embodiment of the present disclosure;

FIG. 6 illustrated the second embodiment of scenario 1 according to anembodiment of the present disclosure;

FIG. 7 is a flowchart illustrating the second embodiment of scenario 1according to an embodiment of the present disclosure;

FIG. 8 illustrates the third embodiment of scenario 1 according to anembodiment of the present disclosure;

FIG. 9 is a flowchart illustrating the third embodiment of scenario 1according to an embodiment of the present disclosure;

FIG. 10 illustrates the fourth embodiment of scenario 1 according to anembodiment of the present disclosure;

FIG. 11 is a flowchart illustrating the fourth embodiment of scenario 1according to an embodiment of the present disclosure;

FIG. 12 illustrates the fifth embodiment of scenario 1 according to anembodiment of the present disclosure;

FIG. 13 is a flowchart illustrating the fifth embodiment of scenario 1according to an embodiment of the present disclosure;

FIG. 14 illustrates an interruption of at least is due to the sensingaccording to scenario 2 according to an embodiment of the presentdisclosure;

FIG. 15 illustrated the first embodiment of scenario 2 according to anembodiment of the present disclosure;

FIG. 16 is a flowchart illustrating the first embodiment of scenario 2according to an embodiment of the present disclosure;

FIG. 17 illustrates an interruption of at least is due to the sensingaccording to scenario 3 according to an embodiment of the presentdisclosure;

FIG. 18 illustrates the first embodiment of scenario 3 according to anembodiment of the present disclosure;

FIG. 19 is a flowchart illustrating the first embodiment of scenario 3according to an embodiment of the present disclosure;

FIG. 20 illustrates the second embodiment of scenario 3 according to anembodiment of the present disclosure;

FIG. 21 is a flowchart illustrating the second embodiment of scenario 3according to an embodiment of the present disclosure;

FIG. 22 illustrates the third embodiment of scenario 3 according to anembodiment of the present disclosure;

FIG. 23 is a flowchart illustrating the third embodiment of scenario 3according to an embodiment of the present disclosure;

FIG. 24 illustrates the fourth embodiment of scenario 3 according to anembodiment of the present disclosure;

FIG. 25 is a flowchart illustrating the fourth embodiment of scenario 3according to an embodiment of the present disclosure;

FIG. 26 illustrates an interruption of at least is due to the sensingaccording to scenario 4 according to an embodiment of the presentdisclosure;

FIG. 27 is a flowchart illustrating the fifth embodiment of scenario 4according to an embodiment of the present disclosure;

FIG. 28 illustrates an evolved Node B (eNB) apparatus according to anembodiment of the present disclosure; and

FIG. 29 illustrates a UE apparatus according to an embodiment of thepresent disclosure.

Throughout the drawings, it should be noted that like reference numbersare used to depict the same or similar elements, features, andstructures.

DETAILED DESCRIPTION

The following description with reference to the accompanying drawings isprovided to assist in a comprehensive understanding of variousembodiments of the present disclosure as defined by the claims and theirequivalents. It includes various specific details to assist in thatunderstanding but these are to be regarded as merely exemplary.Accordingly, those of ordinary skill in the art will recognize thatvarious changes and modifications of the various embodiments describedherein can be made without departing from the scope and spirit of thepresent disclosure. In addition, descriptions of well-known functionsand constructions may be omitted for clarity and conciseness.

The terms and words used in the following description and claims are notlimited to the bibliographical meanings, but, are merely used by theinventor to enable a clear and consistent understanding of the presentdisclosure. Accordingly, it should be apparent to those skilled in theart that the following description of various embodiments of the presentdisclosure is provided for illustration purpose only and not for thepurpose of limiting the present disclosure as defined by the appendedclaims and their equivalents.

It is to be understood that the singular forms “a,” “an,” and “the”include plural referents unless the context clearly dictates otherwise.Thus, for example, reference to “a component surface” includes referenceto one or more of such surfaces.

In each drawing, the same or similar components may be denoted by thesame reference numerals.

Each block of the flowcharts and combinations of the flowcharts may beperformed by computer program instructions. Because these computerprogram instructions may be mounted in processors for a generalcomputer, a special computer, or other programmable data processingapparatuses, these instructions executed by the processors for thecomputer or the other programmable data processing apparatuses createmeans performing functions described in block(s) of the flowcharts.Because these computer program instructions may also be stored in acomputer usable or computer readable memory of a computer or otherprogrammable data processing apparatuses in order to implement thefunctions in a specific scheme, the computer program instructions storedin the computer usable or computer readable memory may also producemanufacturing articles including instruction means performing thefunctions described in block(s) of the flowcharts. Because the computerprogram instructions may also be mounted on the computer or the otherprogrammable data processing apparatuses, the instructions performing aseries of operation on the computer or the other programmable dataprocessing apparatuses to create processes executed by the computer tothereby execute the computer or the other programmable data processingapparatuses may also provide operations for performing the functionsdescribed in block(s) of the flowcharts.

In addition, each block may indicate a module, a segment, and/or a codeincluding one or more executable instructions for executing a specificlogical function(s). Further, functions mentioned in the blocks occurregardless of a sequence in some alternative embodiments. For example,two blocks that are consecutively illustrated may be simultaneouslyperformed in fact or be performed in a reverse sequence depending oncorresponding functions sometimes.

Herein, the term “unit” may include software and/or hardware components,such as a field-programmable gate array (FPGA) and/or anapplication-specific integrated circuit (ASIC). However, the meaning of“unit” is not limited to software and/or hardware. For example, a unitmay be configured to be in a storage medium that may be addressed andmay also be configured to reproduce one or more processor. Accordingly,a “unit” may include components such as software components, objectoriented software components, class components, task components,processors, functions, attributes, procedures, subroutines, segments ofprogram code, drivers, firmware, microcode, circuit, data, database,data structures, tables, arrays, and variables.

Functions provided in the components and the “units” may be combinedwith a smaller number of components and/or “units” or may furtherseparated into additional components and/or “units”.

In addition, components and units may also be implemented to reproduceone or more central processing units (CPUs) within a device or asecurity multimedia card.

The terms as used in the present disclosure are provided to describespecific embodiments, and do not limit the scope of other embodiments.Unless otherwise defined, the terms and words including technical orscientific terms used in the following description and claims may havethe same meanings as generally understood by those skilled in the art.The terms as generally defined in dictionaries may be interpreted ashaving the same or similar meanings as the contextual meanings ofrelated technology. Unless otherwise defined, the terms should not beinterpreted as ideally or excessively formal meanings. When needed, eventhe terms as defined in the present disclosure may not be interpreted asexcluding embodiments of the present disclosure.

Herein, a base station performs resource allocation to a terminal.Examples of the base station may include an eNode B, a Node B, awireless access unit, a base station controller, a node on a network,etc. Examples of the terminal may include a user equipment (UE), amobile station (MS), a cellular phone, a smart phone, a computer, amultimedia system performing a communication function, etc.

Herein, a downlink (DL) is a radio transmission path of a signal from abase station to a UE and an uplink (UL) is a radio transmission path ofa signal from the UE to the base station.

The various embodiments of the present disclosure may be applied toother communication systems having similar technical backgrounds orchannel forms.

Device to Device (D2D) communication enables data communication servicesbetween the UE. During the D2D communication (also referred as sidelink(SL) communication) a transmitting UE can transmit data packets to agroup of UEs or broadcast data packets to all the UEs or send unicastdata packets to a specific UE. UE performs SL communication on subframesdefined over the duration of sidelink control (SLC) period. A subframeis a transmit time interval of duration 1 ms. The SLC period is theperiod over which resources allocated in a cell for SLC information(SLCI) and SL data transmissions occur. Within the SLC period the UEsends SLCI followed by SL data. SLCI indicates destination identifierand characteristics of the transmissions (e.g. modulation and codingscheme (MCS), location of the resource(s) over the duration of SLCperiod, timing alignment).

The UE supporting SL communication can operate in two modes for resourceallocation, scheduled resource allocation and UE autonomous resourceselection. In case of scheduled resource allocation, the UE needs to beRRC_CONNECTED in order to transmit data. The UE requests transmissionresources from the evolved Node B (eNB). The eNB schedules transmissionresources for transmission of SL control information and data. The UEsends a scheduling request (D-SR or Random Access) to the eNB followedby a SL buffer status report (BSR). Based on the SL BSR, the eNB candetermine that the UE has data for a SL communication transmission andestimate the resources needed for transmission. ENB can scheduletransmission resources for SL communication using configured SL radionetwork terminal identifier (SL-RNTI).

In case of UE autonomous resource selection, a UE on its own selectsresources from resource pools and performs transport format selection totransmit SLCI and data. There can be up to 8 transmission pools. Eachpool can have one or more priority associated with it. For transmissionof a medium access control (MAC) protocol data unit (PDU), the UEselects a transmission pool in which one of the associated priorities isequal to the priority of a logical channel with highest priority amongthe logical channel identified in the MAC PDU. There is a one to oneassociation between SLC pool and SL data pool. Once the resource pool isselected, the selection is valid for the entire SLC period. After theSLC period is finished the UE may perform resource pool selection again.

UE interested in D2D communication transmission determines theresource(s) to be used for D2D communication transmission as follows:

UE in radio resource control (RRC) IDLE: eNB can broadcast SLcommunication transmission (TX) resource pool(s) (i.e.commTxPoolNormalCommon) in system information (SI) (e.g. in SI block).If SI includes SL communication TX resource pool(s), UE in RRC IDLEstate autonomously selects the resources from these resource pool(s) forSL communication transmission. If SI does not include SL communicationTX resource pool(s), UE in RRC IDLE state transitions to RRC CONNECTEDand then requests resources from eNB for SL communication transmission.ENB may provide TX resource pool(s) or dedicated resources.

UE in RRC CONNECTED: If UE is in RRC CONNECTED state then it requestsresources from eNB for SL communication transmission. ENB may provide TXresource pool(s) or dedicated resources.

Recently 3rd generation partnership project (3GPP) standard group hasinitiated work item to enhance the SL communication mechanism forvehicle to vehicle (V2V) or vehicle to everything (V2X) (hereinafter,V2V/V2X) communication. One of the enhancements proposed for efficienttransmission is to perform sensing for UE autonomous resource selection.ENB provides TX resource pool. UE autonomously selects the resource(s)from the TX resource pool based on sensing.

FIG. 1 illustrates the timeline for UE autonomous resource selection forV2V/V2X communication according to an embodiment of the presentdisclosure.

If at TTI ‘N’ 120 resource selection/reselection is triggered in UEautonomous resource selection mode, the UE at least senses between TTI‘N-a’ 100 and TTI ‘N-B’ 110, where ‘a’ and ‘b’ are integers and‘a’=Sensing duration+b ms. The sensing duration is 1000 ms 150. Thevalues ‘a’ and ‘b’ are common for V2V/V2X UEs. In UE autonomous resourceselection mode, UE transmits scheduling control info (also referred asscheduling assignment (SA)) at TTI ‘N+c’ 130 indicating the associateddata which is transmitted at TTI ‘N+d’ 140 (d>=c), where ‘c’ and ‘d’ areintegers.

According to this procedure data transmission can be delayed by‘1000+b+c+d’ ms. Assuming values of ‘b’, ‘c’ and ‘d’ to be zero theminimum delay is 1000 ms. The key observations for this procedure are:First UE needs to perform sensing for at least is before selecting theresource. Second, data transmission can be delayed by at least is due tosensing.

The above procedure leads to significant delay in data transmission whenUE initiates V2V/V2X communication transmission. Besides the initialdelay, this procedure also leads to significant interruptions during theongoing data transmissions, for example when UE transitions from idle toconnected state or when TX resource pool is changed in RRC connectedstate or when UE handovers from one cell to another in RRC connectedstate. A method to reduce interruptions is needed.

Scenario 1:

FIG. 2 illustrates the signaling flow according to the scenario 1according to an embodiment of the present disclosure.

UE 200 receives SI including common transmission resource pool i.e.commTxPoolNormalCommon or commTxPoolNormal from eNB 210 at operationS220. UE is in RRC IDLE state and is performing SL V2V/V2X communicationtransmission using common transmission resource pools i.e.commTxPoolNormalCommon or commTxPoolNormal received in SI at operationS230. The commTxPoolNormal (if included) in SI can be included in entryof inter frequency information list (InterFreqInfoList). ThecommTxPoolNormalCommon is transmission resource pool for primary cell(Pcell). UE uses commTxPoolNormalCommon for SL V2V/V2X communicationtransmission if Pcell or Pcell's frequency is used by UE for SL V2V/V2Xcommunication transmission. The commTxPoolNormal is the transmissionresource pool of frequency other than Pcell. UE uses commTxPoolNormal inentry of inter frequency information list (InterFreqInfoList) for thefrequency in which UE want to transmit SL V2V/V2X communication.

UE transitions from RRC IDLE to RRC CONNECTED state for WANcommunication by connection setup at operation S240. In RRC CONNECTEDstate, UE request resources for SL V2V/V2X communication transmission atoperation S250. UE receives Common TX resource pool i.e.commTxPoolNormalDedicated or commTxPoolNormal in dedicated signalingi.e. RRCConnectionReconfiguration message at operation S260. In theRRCConnectionReconfiguration message, the commTxPoolNormal (if included)can be included in entry of inter frequency information list(InterFreqInfoList) for the frequency in which UE want to transmit SLV2V/V2X communication. The commTxPoolNormalDedicated is transmissionresource pool for Pcell. UE uses commTxPoolNormalDedicated for SLV2V/V2X communication transmission if Pcell or Pcell's frequency is usedby UE for SL V2V/V2X communication transmission. The commTxPoolNormal isthe transmission resource pool of frequency other than Pcell. UE usescommTxPoolNormal in entry of inter frequency information list(InterFreqInfoList) for the frequency in which UE want to transmit SLV2V/V2X communication.

UE stops using commTxPoolNormalCommon or commTxPoolNormal received in SIafter receiving the RRCConnectionReconfiguration message at operationS270 and starts using commTxPoolNormalDedicated or commTxPoolNormalreceived in RRCConnectionReconfiguration message for the frequency usedby UE for SL V2V/V2X communication transmission at operation S280.

FIG. 3 illustrates an interruption of at least is due to the sensingaccording to scenario 1 according to an embodiment of the presentdisclosure.

In this procedure, there is an interruption of at least is due tosensing. UE has to switch the resource pool whenRRCConnectionReconfiguration message 320 is received. After switchingthe pool from commTxPoolNormalCommon or commTxPoolNormal 300 received inSI commTxPoolNormalDedicated or commTxPoolNormal 310 received inRRCConnectionReconfiguration message, UE has to start sensing resourcesin commTxPoolNormalDedicated or commTxPoolNormal and sense for at leastsensing duration (e.g. 1 s) before selecting the resource, resulting indelay equal to sensing duration.

FIG. 4 illustrated the first embodiment of scenario 1 according to anembodiment of the present disclosure.

In order to reduce this interruption due to sensing, if UE is usingcommTxPoolNormalCommon or commTxPoolNormal received in SI 400, itcontinues using the commTxPoolNormalCommon or commTxPoolNormal receivedin SI 410 even after receiving the commTxPoolNormalDedicated orcommTxPoolNormal in dedicated signaling i.e.RRCConnectionReconfiguration message 440. UE continues to usecommTxPoolNormalCommon or commTxPoolNormal received in SI 410 while UEis sensing commTxPoolNormalDedicated or commTxPoolNormal received inRRCConnectionReconfiguration 420 after receiving theRRCConnectionReconfiguration including commTxPoolNormalDedicated orcommTxPoolNormal. UE stops using commTxPoolNormalCommon orcommTxPoolNormal received in SI when initial sensing (for specified timeperiod) is completed for commTxPoolNormalDedicated or commTxPoolNormalreceived in RRCConnectionReconfiguration. As seen from FIG. 4, there isno interruption as usage of commTxPoolNormalCommon or commTxPoolNormalreceived in SI is extended until end of initial sensing forcommTxPoolNormalDedicated or commTxPoolNormal received inRRCConnectionReconfiguration.

FIG. 5 is a flowchart illustrating the first embodiment of scenario 1according to an embodiment of the present disclosure.

UE 500 receives SI including common transmission resource pool i.e.commTxPoolNormalCommon or commTxPoolNormal from eNB 510 at operationS520. UE is in RRC IDLE state and is performing SL V2V/V2X communicationtransmission using common transmission resource pools i.e.commTxPoolNormalCommon or commTxPoolNormal received in SI at operationS530. UE transitions from RRC IDLE to RRC CONNECTED state for WANcommunication by connection setup at operation S540 and requestsresources for SL V2V/V2X communication transmission at operation S550.UE receives Common TX resource pool i.e. commTxPoolNormalDedicated orcommTxPoolNormal in dedicated signaling i.e.RRCConnectionReconfiguration message at operation S560 and continues touse commTxPoolNormalCommon or commTxPoolNormal received in SI untilsensing results are available at operation S570. After the sensingresults are available, UE performs SL V2V/V2X communication transmissionusing commTxPoolNormalDedicated or commTxPoolNormal received indedicated signaling i.e. RRCConnectionReconfiguration message atoperation S580.

FIG. 6 illustrated the second embodiment of scenario 1 according to anembodiment of the present disclosure.

In order to reduce this interruption due to sensing, after receiving thecommTxPoolNormalDedicated or commTxPoolNormal in dedicated signalingi.e. RRCConnectionReconfiguration message 640, UE can use thecommTxPoolNormalDedicated or commTxPoolNormal received inRRCConnectionReconfiguration 610 after receiving theRRCConnectionReconfiguration without sensing while it is performinginitial sensing (for specified time period) on commTxPoolNormalDedicatedor commTxPoolNormal 620. As seen from FIG. 6, there is no interruptionas usage of commTxPoolNormalDedicated or commTxPoolNormal received inRRCConnectionReconfiguration is allowed without sensing until end ofinitial sensing for commTxPoolNormalDedicated or commTxPoolNormalreceived in RRCConnectionReconfiguration. After sensing, UE uses thecommTxPoolNormalDedicated or commTxPoolNormal received inRRCConnectionReconfiguration based on sensing results 630.

FIG. 7 is a flowchart illustrating the second embodiment of scenario 1according to an embodiment of the present disclosure.

UE 700 receives SI including common transmission resource pool i.e.commTxPoolNormalCommon or commTxPoolNormal from eNB 710 at operationS720. UE is in RRC IDLE state and is performing SL V2V/V2X communicationtransmission using common transmission resource pools i.e.commTxPoolNormalCommon or commTxPoolNormal received in SI at operationS730. UE transitions from RRC IDLE to RRC CONNECTED state for WANcommunication by connection setup at operation S740. In RRC CONNECTEDstate, UE request resources for SL V2V/V2X communication transmission atoperation S750. UE receives Common TX resource pool i.e.commTxPoolNormalDedicated or commTxPoolNormal in dedicated signalingi.e. RRCConnectionReconfiguration message at operation S760. Afterreceiving RRCConnectionReconfiguration message, UE stops usingcommTxPoolNormalCommon or commTxPoolNormal at operation S770 received inSI and starts using commTxPoolNormalDedicated or commTxPoolNormalreceived in dedicated signaling until the sensing results are availableat operation S780. The resources are randomly selected fromcommTxPoolNormalDedicated or commTxPoolNormal received in dedicatedsignaling. After the sensing results are available, UE usescommTxPoolNormalDedicated or commTxPoolNormal received in dedicatedsignaling to perform SL V2V/V2X communication at operation S790. Theresources are selected from commTxPoolNormalDedicated orcommTxPoolNormal based on the sensing results.

FIG. 8 illustrates the third embodiment of scenario 1 according to anembodiment of the present disclosure.

In order to reduce this interruption due to sensing, after receiving thecommTxPoolNormalDedicated or commTxPoolNormal in dedicated signalingi.e. RRCConnectionReconfiguration message 830, UE performs sensing ofthe commTxPoolNormalDedicated or commTxPoolNormal received inRRCConnectionReconfiguration in short duration (e.g. 250 ms) for adefied time period T 810. T>=duration for normal sensing i.e. 1000 ms.UE can use the commTxPoolNormalDedicated or commTxPoolNormal received inRRCConnectionReconfiguration after short sensing duration 820.

FIG. 9 is a flowchart illustrating the third embodiment scenario 1according to an embodiment of the present disclosure.

UE 900 receives SI including common transmission resource pool i.e.commTxPoolNormalCommon or commTxPoolNormal from eNB 910 at operationS920. UE is in RRC IDLE state and is performing SL V2V/V2X communicationtransmission using common transmission resource pools i.e.commTxPoolNormalCommon or commTxPoolNormal received in SI at operationS930. UE transitions from RRC IDLE to RRC CONNECTED state for WANcommunication by connection setup at operation S940. In RRC CONNECTEDstate, UE request resources for SL V2V/V2X communication transmission atoperation S950. UE receives Common TX resource pool i.e.commTxPoolNormalDedicated or commTxPoolNormal in dedicated signalingi.e. RRCConnectionReconfiguration message at operation S960. Afterreceiving RRCConnectionReconfiguration message, UE stops usingcommTxPoolNormalCommon or commTxPoolNormal at operation S970 received inSI. UE performs short duration sensing of commTxPoolNormalDedicated orcommTxPoolNormal received in RRCConnectionReconfiguration message. Whenshort sensing period expires, UE starts using commTxPoolNormalDedicatedor commTxPoolNormal based on short sensing results until the sensingresults of normal sensing are available at operation S980. After thesensing results of normal sensing are available, UE usescommTxPoolNormalDedicated or commTxPoolNormal based on the sensingresults of normal sensing at operation S990.

FIG. 10 illustrates the fourth embodiment of scenario 1 according to anembodiment of the present disclosure.

In order to reduce this interruption due to sensing, eNB can signal twosets of TX resource pool(s), commTxPoolNormalDedicated1 orcommTxPoolNormal1 and commTxPoolNormalDedicated2 or commTxPoolNormal2 indedicated signaling i.e. RRCConnectionReconfiguration message. Afterreceiving the RRCConnectionReconfiguration UE starts sensing forcommTxPoolNormalDedicated2 or commTxPoolNormal2 1020 and usescommTxPoolNormalDedicated1 or commTxPoolNormal1 1010 while UE is sensingcommTxPoolNormalDedicated2 or commTxPoolNormal2. UE stops usingcommTxPoolNormalCommon or commTxPoolNormal received in SI 1000 afterreceiving RRCConnectionReconfiguration message 1040. UE stops usingcommTxPoolNormalDedicated1 or commTxPoolNormal1 received inRRCConnectionReconfiguration after initial sensing (for specified timeperiod) is done for commTxPoolNormalDedicated2 or commTxPoolNormal2 andstarts using commTxPoolNormalDedicated2 or commTxPoolNormal2 1030 basedon sensing results.

FIG. 11 is a flowchart illustrating the fourth embodiment of scenario 1according to an embodiment of the present disclosure.

UE 1100 receives SI including common transmission resource pool i.e.commTxPoolNormalCommon or commTxPoolNormal from eNB 1110 at operationS1120. UE is in RRC IDLE state and is performing SL V2V/V2Xcommunication transmission using common transmission resource pools i.e.commTxPoolNormalCommon or commTxPoolNormal received in SI at operationS1130. UE transitions from RRC IDLE to RRC CONNECTED state for WANcommunication by connection setup at operation S1140. In RRC CONNECTEDstate, UE request resources for SL V2V/V2X communication transmission atoperation S1150. UE receives Common TX resource pool i.e.commTxPoolNormalDedicated1, commTxPoolNormalDedicated2 orcommTxPoolNormal1, commTxPoolNormal2 in dedicated signaling i.e.RRCConnectionReconfiguration message at operation S1160. After receivingRRCConnectionReconfiguration message, UE stops usingcommTxPoolNormalCommon or commTxPoolNormal at operation S1170 and startsusing commTxPoolNormalDedicated1 or commTxPoolNormal1 until the sensingresults for commTxPoolNormalDedicated2 or commTxPoolNormal2 areavailable at operation S1180. The resources are randomly selected fromcommTxPoolNormalDedicated1 or commTxPoolNormal1. After the sensingresults for commTxPoolNormalDedicated2 or commTxPoolNormal2 areavailable, UE starts to perform SL V2V/V2X communication usingcommTxPoolNormalDedicated2 or commTxPoolNormal2 based on the sensingresult at operation S1190. The resources are selected fromcommTxPoolNormalDedicated2 or commTxPoolNormal2 based on sensing result.

FIG. 12 illustrates the fifth embodiment of scenario 1 according to anembodiment of the present disclosure.

In order to reduce this interruption due to sensing, eNB can signaltransmission resource pool configurations for autonomous resourceselection i.e. commTxPoolNormalDedicated or commTxPoolNormal indedicated signaling (RRCConnectionReconfiguration message) andexceptional transmission resource pool i.e. commTxPoolExceptional inbroadcast signaling SI. The commTxPoolExceptional can also be includedin dedicated signaling (RRCConnectionReconfiguration message). In theRRCConnectionReconfiguration message, the commTxPoolNormal (if included)can be included in entry of inter frequency information list(InterFreqInfoList) for the frequency in which UE want to transmit SLV2V/V2X communication. In the SI, the commTxPoolExceptional (ifincluded) for non-serving frequency can be included in entry of interfrequency information list (InterFreqInfoList) for the frequency inwhich UE want to transmit SL V2V/V2X communication. In the SI, thecommTxPoolExceptional (if included) for serving frequency (i.e.frequency of Pcell) can be included as part of common configuration. Inthe RRCConnectionReconfiguration message, the commTxPoolExceptional (ifincluded) can be included in entry of inter frequency information list(InterFreqInfoList) for the frequency in which UE want to transmit SLV2V/V2X communication. After receiving the RRCConnectionReconfigurationmessage including transmission resource pool configurations forautonomous resource selection i.e. commTxPoolNormalDedicated orcommTxPoolNormal 1240, UE uses commTxPoolExceptional (if signaled eitherin broadcast or dedicated signaling for the concerned frequency) withoutsensing (i.e. randomly select resources from the resource pool) while UEis performing sensing on the resources included incommTxPoolNormalDedicated 1210. UE stops using commTxPoolNormalCommonafter receiving RRCConnectionReconfiguration message 1200. UE stopsusing commTxPoolExceptional after initial sensing is completed on theresources included in commTxPoolNormalDedicated or commTxPoolNormal1220. No sensing is performed for usage (or selecting resources) ofcommTxPoolExceptional. Alternately sensing can be performed forcommTxPoolExceptional while UE is using commTxPoolNormalCommon.Alternately sensing can be started for commTxPoolExceptionalCommon afterthe connection is initiated. Sensing period for commTxPoolExceptionalcan be smaller (pre-defined or signaled) than normal sensing duration.

FIG. 13 is a flowchart illustrating the fifth embodiment of scenario 1according to an embodiment of the present disclosure.

UE 1300 receives SI including common transmission resource pool i.e.commTxPoolNormalCommon or commTxPoolNormal from eNB 1310 at operationS1320. UE is in RRC IDLE state and is performing SL V2V/V2Xcommunication transmission using common transmission resource pools i.e.commTxPoolNormalCommon or commTxPoolNormal received in SI at operationS1330. UE transitions from RRC IDLE to RRC CONNECTED state for WANcommunication by connection setup at operation S1340. In RRC CONNECTEDstate, UE request resources for SL V2V/V2X communication transmission atoperation S1350. UE receives Common TX resource pool i.e.commTxPoolNormalDedicated or commTxPoolNormal in dedicated signalingi.e. RRCConnectionReconfiguration message at operation S1360. Afterreceiving RRCConnectionReconfiguration message, UE stops usingcommTxPoolNormalCommon or commTxPoolNormal at operation S1370. UE startsusing commTxPoolExceptional without sensing until the sensing resultsare available for commTxPoolNormalDedicated or commTxPoolNormal atoperation S1380. The resources are randomly selected fromcommTxPoolExceptional. After the sensing results are available, UEperforms SL V2V/V2X communication transmission usingcommTxPoolNormalDedicated or commTxPoolNormal at operation S1390. Theresources are selected based on the sensing results.

In an alternate embodiment of the present disclosure, in response to SLcommunication request eNB may signal (e.g. using one bit indication) inRRCConnectionReconfiguration message to use the commTxPoolNormalCommonwhich is broadcasted in SIB instead of signalingcommTxPoolNormalDedicated. As a result, UE does not have to switch fromcommTxPoolNormalCommon commTxPoolNormalDedicated and hence nointerruption.

In an alternate embodiment of the present disclosure, eNB may indicate(e.g. one bit indicator) in broadcast signaling that UE can continue touse commTxPoolNormalCommon which is broadcasted in SIB in RRC connectedstate. UE does not need to request for resources in RRC connected stateor when UE transitions from RRC Idle to RRC Connected. As a result, UEdoes not request new resources and does not have to switch fromcommTxPoolNormalCommon commTxPoolNormalDedicated and hence nointerruption.

In an alternate embodiment of the present disclosure, eNB may signalcommTxPoolNormalDedicated and also signal (e.g. using one bitindication) that commTxPoolNormalDedicated is same ascommTxPoolNormalCommon or is a subset of commTxPoolNormalCommon inRRCConnectionReconfiguration message. As a result, UE does not have toinitiate sensing again as UE is already performing sensing.

Scenario 2:

UE is in RRC IDLE. Common TX resource pools i.e. commTxPoolNormalCommonis not broadcasted in SI. UE transitions from RRC IDLE to RRC CONNECTEDto request resources for SL V2V/V2X communication transmission. UEperforms sidelink communication transmission using commTxPoolExceptionalreceived in SI after initiating the connection. In the SI, thecommTxPoolExceptional (if included) for non-serving frequency can beincluded in entry of inter frequency information list(InterFreqInfoList) for the frequency in which UE want to transmitsidelink V2V/V2X communication. In the SI, the commTxPoolExceptional (ifincluded) for serving frequency (i.e. frequency of Pcell) can beincluded as part of common configuration.

UE receives Common TX resource pools i.e. commTxPoolNormalDedicated orcommTxPoolNormal in dedicated signaling i.e.RRCConnectionReconfiguration message. UE stops usingcommTxPoolExceptional and starts using commTxPoolNormalDedicated orcommTxPoolNormal. In the RRCConnectionReconfiguration message, thecommTxPoolNormal (if included) can be included in entry of interfrequency information list (InterFreqInfoList) for the frequency inwhich UE want to transmit SL V2V/V2X communication. ThecommTxPoolNormalDedicated is transmission resource pool for Pcell. UEuses commTxPoolNormalDedicated for SL V2V/V2X communication transmissionif Pcell or Pcell's frequency is used by UE for SL V2V/V2X communicationtransmission. The commTxPoolNormal is the transmission resource pool offrequency other than Pcell. UE uses commTxPoolNormal in entry of interfrequency information list (InterFreqInfoList) for the frequency inwhich UE want to transmit SL V2V/V2X communication.

FIG. 14 illustrates an interruption of at least is due to the sensingaccording to scenario 2 according to an embodiment of the presentdisclosure.

In this procedure, there is an interruption of at least is due tosensing. After switching the pool from commTxPoolExceptional 1400commTxPoolNormalDedicated or commTxPoolNormal 1410, UE has to startsensing for commTxPoolNormalDedicated or commTxPoolNormal resulting indelay of at least 1 s.

If the time X between connection initiation and reception ofcommTxPoolNormalDedicated or commTxPoolNormal inRRCConnectionReconfiguration is smaller than ‘1000+b+c+d’ ms and UEswitches from commTxPoolExceptional to commTxPoolNormalDedicated orcommTxPoolNormal after receiving commTxPoolNormalDedicated inRRCConnectionReconfiguration 1420 then there is no benefit of usage ofexceptional pool. There will be delay of at least 1000+X ms in SLcommunication transmission.

FIG. 15 illustrated the first embodiment of scenario 2 according to anembodiment of the present disclosure.

In order to reduce this interruption due to sensing, if UE is usingcommTxPoolExceptional 1500, it continues using the commTxPoolExceptional1510 even after receiving the commTxPoolNormalDedicated orcommTxPoolNormal in dedicated signaling i.e.RRCConnectionReconfiguration message. UE continues to usecommTxPoolExceptional while UE is sensing commTxPoolNormalDedicated orcommTxPoolNormal 1520 after receiving the RRCConnectionReconfigurationincluding commTxPoolNormalDedicated or commTxPoolNormal 1540. UE stopsusing commTxPoolExceptional when initial sensing (for specified period)is completed for commTxPoolNormalDedicated or commTxPoolNormal. As seenfrom FIG. 15, there is no interruption after receivingRRCConnectionReconfiguration as usage of commTxPoolExceptional isextended until end of initial sensing for commTxPoolNormalDedicated orcommTxPoolNormal. The commTxPoolExceptional can also be included indedicated signaling (RRCConnectionReconfiguration message). In theRRCConnectionReconfiguration message, the commTxPoolNormal (if included)can be included in entry of inter frequency information list(InterFreqInfoList) for the frequency in which UE want to transmit SLV2V/V2X communication. In the SI, the commTxPoolExceptional (ifincluded) for non-serving frequency can be included in entry of interfrequency information list (InterFreqInfoList) for the frequency inwhich UE want to transmit SL V2V/V2X communication. In the SI, thecommTxPoolExceptional (if included) for serving frequency (i.e.frequency of Pcell) can be included as part of common configuration.

The interruption between connection initiation and reception ofcommTxPoolNormalDedicated or commTxPoolNormal inRRCConnectionReconfiguration can be reduced by relaxing the sensing timefor commTxPoolExceptional. UE can select the resource fromcommTxPoolExceptional without sensing. Alternately UE can select theresource from commTxPoolExceptional after shorter sensing duration. Thesensing duration for commTxPoolExceptional can be much smaller thannormal Tx pools.

FIG. 16 is a flowchart illustrating the first embodiment of scenario 2according to an embodiment of the present disclosure.

UE 1600 receives SI including exceptional transmission resource pooli.e. commTxPoolExceptional from eNB 1610 at operation S1620. UE isperforming SL V2V/V2X communication transmission usingcommTxPoolExceptional received in SI from the moment when RRC connectionrequest is transmitted at operation S1630. The resources are randomlyselected from commTxPoolExceptional. UE transitions from RRC IDLE to RRCCONNECTED state for WAN communication by connection setup at operationS1640 and requests resources for SL V2V/V2X communication transmissionat operation S1650. UE receives Common TX resource pool i.e.commTxPoolNormalDedicated or commTxPoolNormal in dedicated signalingi.e. RRCConnectionReconfiguration message at operation S1660. UEcontinues to use commTxPoolExceptional until sensing results areavailable for commTxPoolNormalDedicated or commTxPoolNormal at operationS1670. The resources are randomly selected from commTxPoolExceptional.After the sensing results are available, UE performs SL V2V/V2Xcommunication transmission using commTxPoolNormalDedicated orcommTxPoolNormal in dedicated signaling i.e.RRCConnectionReconfiguration message at operation S1680. The resourcesare selected from commTxPoolNormalDedicated or commTxPoolNormal based onsensing result.

In second embodiment of scenario 2, in order to reduce this interruptiondue to sensing, after receiving the commTxPoolNormalDedicated orcommTxPoolNormal in dedicated signaling i.e.RRCConnectionReconfiguration message, UE can use thecommTxPoolNormalDedicated or commTxPoolNormal after receiving theRRCConnectionReconfiguration without sensing while it is performingsensing on commTxPoolNormalDedicated or commTxPoolNormal. After sensingon commTxPoolNormalDedicated or commTxPoolNormal, UE can usecommTxPoolNormalDedicated or commTxPoolNormal based on the sensingresults. The interruption between connection initiation and reception ofcommTxPoolNormalDedicated or commTxPoolNormal inRRCConnectionReconfiguration can be reduced by allowing usage ofcommTxPoolExceptional with relaxed sensing time. UE can select theresource from commTxPoolExceptional without sensing. Alternately UE canselect the resource from commTxPoolExceptional after shorter sensingduration. The sensing duration for commTxPoolExceptional can be muchsmaller than normal Tx pools. UE stops using commTxPoolException afterreceiving RRCConnectionReconfiguration message.

In third embodiment of the present disclosure for scenario 2, in orderto reduce this interruption due to sensing, after receiving thecommTxPoolNormalDedicated or commTxPoolNormal in dedicated signalingi.e. RRCConnectionReconfiguration message, UE can use thecommTxPoolNormalDedicated or commTxPoolNormal after receiving theRRCConnectionReconfiguration with short sensing duration (e.g. 250 ms)for a defined time period T. T>=duration for normal sensing i.e. 1000ms. The interruption between connection initiation and reception ofcommTxPoolNormalDedicated or commTxPoolNormal inRRCConnectionReconfiguration can be reduced by allowing usage ofcommTxPoolExceptional with short sensing time. UE can select theresource from commTxPoolExceptional without sensing. Alternately UE canselect the resource from commTxPoolExceptional after shorter sensingduration. The sensing duration for commTxPoolExceptional can be muchsmaller than normal Tx pools. UE stops using commTxPoolException afterreceiving RRCConnectionReconfiguration message.

In fourth embodiment of the present disclosure for scenario 2, in orderto reduce this interruption due to sensing, eNB can signal two sets ofTX resource pool(s), commTxPoolNormalDedicated1 andcommTxPoolNormalDedicated2 in dedicated signaling i.e.RRCConnectionReconfiguration message. After receiving theRRCConnectionReconfiguration UE starts sensing forcommTxPoolNormalDedicated2 and uses commTxPoolNormalDedicated1 while UEis sensing commTxPoolNormalDedicated2. UE stops usingcommTxPoolException after receiving RRCConnectionReconfigurationmessage. UE stops using commTxPoolNormalDedicated1 after initial sensingis done for commTxPoolNormalDedicated2.

Scenario 3:

FIG. 17 illustrates an interruption of at least is due to the sensingaccording to scenario 3 according to an embodiment of the presentdisclosure.

UE is in RRC CONNECTED. UE is interested in SL V2V/V2X communicationtransmission and requests SL common transmission resource 1720. UEreceives Common TX resource pools i.e. commTxPoolNormalDedicated orcommTxPoolNormal in dedicated signaling i.e.RRCConnectionReconfiguration message 1710. In this procedure, there isan interruption of at least is due to sensing as UE can select resourcefrom commTxPoolNormalDedicated or commTxPoolNormal only after sensing1700. The same interruption will also occur whencommTxPoolNormalDedicated or commTxPoolNormal configured byRRCConnectionReconfiguration message is reconfigured by anotherRRCConnectionReconfiguration message. In theRRCConnectionReconfiguration message, the commTxPoolNormal (if included)can be included in entry of inter frequency information list(InterFreqInfoList) for the frequency in which UE want to transmit SLV2V/V2X communication. The commTxPoolNormalDedicated is transmissionresource pool for Pcell. The commTxPoolNormal is the transmissionresource pool of frequency other than Pcell.

FIG. 18 illustrates the first embodiment of scenario 3 according to anembodiment of the present disclosure.

In order to reduce this interruption due to sensing, after receiving thecommTxPoolNormalDedicated or commTxPoolNormal in dedicated signalingi.e. RRCConnectionReconfiguration message 1820, UE use the receivedcommTxPoolNormalDedicated or commTxPoolNormal 1800 after receiving theRRCConnectionReconfiguration without sensing while it is performinginitial sensing (for specified period) on commTxPoolNormalDedicated orcommTxPoolNormal 1830. After the sensing results are available, UE canuse the received commTxPoolNormalDedicated or commTxPoolNormal based onthe sensing results 1810. If commTxPoolNormalDedicated orcommTxPoolNormal was configured previously before receiving thisRRCConnectionReconfiguration message, UE stops using thatcommTxPoolNormalDedicated or commTxPoolNormal after receiving thisRRCConnectionReconfiguration message.

FIG. 19 is a flowchart illustrating the first embodiment of scenario 3according to an embodiment of the present disclosure.

UE 1900 receives Common TX resource pool i.e. commTxPoolNormalDedicatedor commTxPoolNormal in dedicated signaling i.e.RRCConnectionReconfiguration message from eNB 1910 at operation S1920.UE uses commTxPoolNormalDedicated or commTxPoolNormal until sensingresults are available for commTxPoolNormalDedicated or commTxPoolNormalat operation S1930. The resources are randomly selected fromcommTxPoolNormalDedicated or commTxPoolNormal. After the sensing resultsare available, UE performs SL V2V/V2X communication transmission usingcommTxPoolNormalDedicated or commTxPoolNormal at operation S1940. Theresources are selected from commTxPoolNormalDedicated orcommTxPoolNormal based on sensing result.

FIG. 20 illustrates the second embodiment of scenario 3 according to anembodiment of the present disclosure.

In order to reduce this interruption due to sensing, after receiving thecommTxPoolNormalDedicated or commTxPoolNormal in dedicated signalingi.e. RRCConnectionReconfiguration message 2020, UE can use the receivedcommTxPoolNormalDedicated or commTxPoolNormal after receiving theRRCConnectionReconfiguration with short sensing duration (e.g. 250 ms)for a defined time period T 2000. T>=duration for normal sensing i.e.1000 ms. If commTxPoolNormalDedicated or commTxPoolNormal was configuredpreviously before receiving this RRCConnectionReconfiguration message,UE stops using that commTxPoolNormalDedicated or commTxPoolNormal afterreceiving this RRCConnectionReconfiguration message.

FIG. 21 is a flowchart illustrating the second embodiment of scenario 3according to an embodiment of the present disclosure.

UE 2100 receives Common TX resource pool i.e. commTxPoolNormalDedicatedor commTxPoolNormal in dedicated signaling i.e.RRCConnectionReconfiguration message from eNB 2110 at operation S2120.UE uses commTxPoolNormalDedicated or commTxPoolNormal when short sensingresults are available for commTxPoolNormalDedicated or commTxPoolNormalat operation S2130. The resources are selected fromcommTxPoolNormalDedicated or commTxPoolNormal based on the short sensingresults. After the normal sensing results are available, UE performs SLV2V/V2X communication transmission using commTxPoolNormalDedicated orcommTxPoolNormal at operation S2140. The resources are selected fromcommTxPoolNormalDedicated or commTxPoolNormal based on the normalsensing result.

FIG. 22 illustrates the third embodiment of scenario 3 according to anembodiment of the present disclosure.

In order to reduce this interruption due to sensing, eNB can signal twosets of TX resource pool(s), commTxPoolNormalDedicated1 andcommTxPoolNormalDedicated2 in dedicated signaling i.e.RRCConnectionReconfiguration message 2220. After receiving theRRCConnectionReconfiguration UE starts sensing forcommTxPoolNormalDedicated2 and uses commTxPoolNormalDedicated1 2200while UE is sensing commTxPoolNormalDedicated2 2230. UE stops usingcommTxPoolNormalDedicated1 after initial sensing is done forcommTxPoolNormalDedicated2 2210. If commTxPoolNormalDedicated orcommTxPoolNormal was configured previously before receiving thisRRCConnectionReconfiguration message, UE stops using thatcommTxPoolNormalDedicated or commTxPoolNormal after receiving thisRRCConnectionReconfiguration message.

FIG. 23 is a flowchart illustrating the third embodiment of scenario 3according to an embodiment of the present disclosure.

UE 2300 receives Common TX resource pool i.e. commTxPoolNormalDedicated1and commTxPoolNormalDedicated2 or commTxPoolNormal1 andcommTxPoolNormal2 in dedicated signaling i.e.RRCConnectionReconfiguration message from eNB 2310 at operation S2320.UE uses commTxPoolNormalDedicated1 or commTxPoolNormal1 when sensingresults on commTxPoolNormalDedicated2 or commTxPoolNormal2 are availableat operation S2330. The resources are randomly selected fromcommTxPoolNormalDedicated1 or commTxPoolNormal1. After the sensingresults are available, UE performs SL V2V/V2X communication transmissionusing commTxPoolNormalDedicated2 or commTxPoolNormal2 at operationS2340. The resources are selected from commTxPoolNormalDedicated2 orcommTxPoolNormal2 based on the normal sensing result.

FIG. 24 illustrates the fourth embodiment of scenario 3 according to anembodiment of the present disclosure.

In order to reduce this interruption due to sensing, eNB can signaltransmission resource pool configurations for autonomous resourceselection i.e. commTxPoolNormalDedicated or commTxPoolNormal indedicated signaling i.e. RRCConnectionReconfiguration message 2420 andexceptional transmission resource pool i.e. commTxPoolExceptional inbroadcast signaling SI.

The commTxPoolExceptional can also be included in dedicated signaling(RRCConnectionReconfiguration message). In theRRCConnectionReconfiguration message, the commTxPoolNormal (if included)can be included in entry of inter frequency information list(InterFreqInfoList) for the frequency in which UE want to transmit SLV2V/V2X communication. In the SI, the commTxPoolExceptional (ifincluded) for non-serving frequency can be included in entry of interfrequency information list (InterFreqInfoList) for the frequency inwhich UE want to transmit SL V2V/V2X communication. In the SI, thecommTxPoolExceptional (if included) for serving frequency (i.e.frequency of Pcell) can be included as part of common configuration. Inthe RRCConnectionReconfiguration message, the commTxPoolExceptional (ifincluded) can be included in entry of inter frequency information list(InterFreqInfoList) for the frequency in which UE want to transmit SLV2V/V2X communication.

After receiving the RRCConnectionReconfiguration, including transmissionresource pool configurations for autonomous resource selection i.e.commTxPoolNormalDedicated or commTxPoolNormal, UE usescommTxPoolExceptional (if signaled either in broadcast or dedicatedsignaling for the concerned frequency) without sensing (i.e. randomlyselect resources from the resource pool) 2400 while UE is performingsensing on the resources included in commTxPoolNormalDedicated 2430. UEstops using commTxPoolExceptional after initial sensing is completed onthe resources included in commTxPoolNormalDedicated or commTxPoolNormal2410. No sensing is performed for usage of commTxPoolExceptional.Alternately sensing can be performed for commTxPoolExceptional whereinsensing period for commTxPoolExceptional can be smaller (pre-defined orsignaled) than normal sensing duration. If commTxPoolNormalDedicated orcommTxPoolNormal was configured previously before receiving thisRRCConnectionReconfiguration message, UE stops using thatcommTxPoolNormalDedicated or commTxPoolNormal after receiving thisRRCConnectionReconfiguration message.

FIG. 25 is a flowchart illustrating the fourth embodiment of scenario 3according to an embodiment of the present disclosure.

UE 2500 receives Common TX resource pool i.e. commTxPoolNormalDedicatedor commTxPoolNormal in dedicated signaling i.e.RRCConnectionReconfiguration message from eNB 2510 at operation S2520.UE uses commTxPoolExceptional until the sensing results oncommTxPoolNormalDedicated or commTxPoolNormal are available at operationS2530. The resources are randomly selected from commTxPoolExceptional.UE can receive commTxPoolExceptional by broadcast signaling or dedicatedsignaling. After the sensing results are available, UE performs SLV2V/V2X communication transmission using commTxPoolNormalDedicated orcommTxPoolNormal at operation S2540. The resources are selected fromcommTxPoolNormalDedicated or commTxPoolNormal based on the sensingresult.

Scenario 4 (Handover):

FIG. 26 illustrates an interruption of at least is due to the sensingaccording to scenario 4 according to an embodiment of the presentdisclosure.

UE is in RRC CONNECTED. UE is performing SL V2V/V2X communicationtransmission in source cell 2600. UE handovers from source cell totarget cell. In the handover command (or RRCConnectionReconfigurationwith mobilityControl IE) UE receives transmission resource poolconfigurations for autonomous resource selection i.e.commTxPoolNormalDedicated or commTxPoolNormal 2620. In the handovercommand (or RRCConnectionReconfiguration), the commTxPoolNormal can beincluded in entry of inter frequency information list(InterFreqInfoList) for the frequency in which UE want to transmit SLV2V/V2X communication. The handover command is received by UE fromsource cell. In this procedure, there is an interruption of at least 1 sdue to sensing, as UE can select resource from receivedcommTxPoolNormalDedicated or commTxPoolNormal of target cell only aftersensing 2610.

In the first embodiment of the present disclosure for scenario 4, inorder to reduce this interruption due to sensing, after receiving thetransmission resource pool configurations for autonomous resourceselection i.e. commTxPoolNormalDedicated or commTxPoolNormal in handovercommand (or RRCConnectionReconfiguration), UE can use i.e. selectresource from commTxPoolNormalDedicated or commTxPoolNormal withoutsensing (i.e. randomly select resource from resource pool) while it isperforming sensing on commTxPoolNormalDedicated or commTxPoolNormal.Once the initial sensing is completed, UE does not randomly selectresource from commTxPoolNormalDedicated or commTxPoolNormal but selectresources based on sensing result. In an example, duration for normalsensing can be 1000 ms. In the handover command (orRRCConnectionReconfiguration), the commTxPoolNormal can be included ininter frequency information list (InterFreqInfoList). UE uses thecommTxPoolNormal in the entry of InterFreqInfoList for the frequency inwhich UE want to transmit SL V2V/V2X communication.

In the second embodiment of the present disclosure for scenario 4, inorder to reduce this interruption due to sensing, after receiving thetransmission resource pool configurations for autonomous resourceselection i.e. commTxPoolNormalDedicated or commTxPoolNormal in handovercommand, UE can use i.e. select resource from commTxPoolNormalDedicatedor commTxPoolNormal with short sensing duration (e.g. 250 ms) for adefined time period T. T<duration for normal sensing. In an example,duration for normal sensing can be 1000 ms. In the handover command (orRRCConnectionReconfiguration), the commTxPoolNormal can be included ininter frequency information list (InterFreqInfoList). UE uses thecommTxPoolNormal in the entry of InterFreqInfoList for the frequency inwhich UE want to transmit SL V2V/V2X communication.

In the third embodiment of the present disclosure for scenario 4, inorder to reduce this interruption due to sensing, two sets of TXresource pool(s), commTxPoolNormalDedicated1 or commTxPoolNormal1 andcommTxPoolNormalDedicated2 or commTxPoolNormal2 can be signaled inhandover command UE uses commTxPoolNormalDedicated1 or commTxPoolNormal1without sensing (i.e. randomly select resource from resource pool) whileUE is sensing commTxPoolNormalDedicated2 or commTxPoolNormal2. UE stopsusing commTxPoolNormalDedicated1 or commTxPoolNormal1 after initialsensing is done for commTxPoolNormalDedicated2 or commTxPoolNormal2. Inan example, duration for initial sensing can be 1000 ms. In the handovercommand (or RRCConnectionReconfiguration), the commTxPoolNormal1 andcommTxPoolNormal2 can be included in inter frequency information list(InterFreqInfoList). UE uses the commTxPoolNormal1 and commTxPoolNormal2in the entry of InterFreqInfoList for the frequency in which UE want totransmit SL V2V/V2X communication.

In the fourth embodiment of the present disclosure for scenario 4,transmission resource pool configurations for autonomous resourceselection i.e. commTxPoolNormalDedicated or commTxPoolNormal aresignaled in handover command (or RRCConnectionReconfiguration message).In the handover command (or RRCConnectionReconfiguration message), thecommTxPoolNormal can be included in entry of InterFreqInfoList for thefrequency in which UE want to transmit SL V2V/V2X communication. Thesource cell can signal exceptional transmission resource pool i.e.commTxPoolExceptional in broadcast signaling i.e. SI or in dedicatedsignaling i.e. RRCConnectionReconfiguration message. UE usescommTxPoolExceptional provided source cell without sensing (i.e.randomly select resource from resource pool) from the reception ofhandover command. Alternately sensing can be performed forcommTxPoolExceptional wherein sensing period for commTxPoolExceptionalcan be smaller (pre-defined or signaled) than normal sensing duration.UE can initiate sensing of commTxPoolExceptional when source cell signalquality goes below a threshold, or when TTT is started or when targetcell quality is above source quality by a threshold, or target cellquality is above a threshold. UE continue to use commTxPoolExceptionaluntil the initial sensing is completed on commTxPoolNormalDedicated orcommTxPoolNormal received in handover command (orRRCConnectionReconfiguration message). In case scheduled resourceallocation is indicated in handover command, UE continue to usecommTxPoolExceptional until the handover is completed i.e. until thetimer associated with handover is running.

In the fifth embodiment of the present disclosure for scenario 4, inorder to reduce this interruption due to sensing, an exceptionaltransmission resource pool i.e. commTxPoolExceptional can be signaled inaddition to transmission resource pool configurations for autonomousresource selection i.e. commTxPoolNormalDedicated or commTxPoolNormal oftarget cell in handover command (or RRCConnectionReconfigurationmessage). In the handover command (or RRCConnectionReconfigurationmessage), the commTxPoolNormal can be included in entry ofInterFreqInfoList for the frequency in which UE want to transmit SLV2V/V2X communication. In the handover command (orRRCConnectionReconfiguration), the commTxPoolNormal can be included inentry of inter frequency information list (InterFreqInfoList) for thefrequency in which UE want to transmit SL V2V/V2X communication. IfcommTxPoolExceptional is received in handover command (orRRCConnectionReconfiguration message), UE uses commTxPoolExceptionalwithout sensing (i.e. randomly select resource from resource pool) fromthe reception of handover command Alternately sensing can be performedfor commTxPoolExceptional wherein sensing period forcommTxPoolExceptional can be smaller (pre-defined or signaled) thannormal sensing duration. UE continue to use commTxPoolExceptional untilthe initial sensing is completed on commTxPoolNormalDedicated orcommTxPoolNormal received in handover command (orRRCConnectionReconfiguration message).

FIG. 27 is a flowchart illustrating the fifth embodiment of scenario 4according to an embodiment of the present disclosure.

Target cell 2720 transmits transmission resource pool configurations forautonomous resource selection i.e. commTxPoolNormalDedicated orcommTxPoolNormal of target cell in Target Configuration to Source cell2710 at operation S2730. Transmission resource pool configurationsfurther comprises commTxPoolExceptional. Source cell transmits handovercommand to a UE 2700 at operation S2740. In the handover command (orRRCConnectionReconfiguration message), commTxPoolNormalDedicated orcommTxPoolNormal and commTxPoolExceptional can be included. IfcommTxPoolExceptional is received in handover command (orRRCConnectionReconfiguration message), UE can perform SL V2V/V2Xcommunication transmission using commTxPoolExceptional until the sensingresults on commTxPoolNormalDedicated or commTxPoolNormal is available atoperation S2750. The resources are randomly selected fromcommTxPoolExceptional. After the sensing results are available, UEperforms SL V2V/V2X communication transmission usingcommTxPoolNormalDedicated or commTxPoolNormal at operation S2760. Theresources are selected from commTxPoolNormalDedicated orcommTxPoolNormal based on sensing result.

In the sixth embodiment of the present disclosure for scenario 4, inorder to reduce this interruption due to sensing, an exceptionaltransmission resource pool i.e. commTxPoolExceptional is signaled inaddition to resource pool configuration of target cell for scheduledresource allocation in handover command (or RRCConnectionReconfigurationmessage). In the handover command (or RRCConnectionReconfiguration), thecommTxPoolNormal can be included in entry of inter frequency informationlist (InterFreqInfoList) for the frequency in which UE want to transmitSL V2V/V2X communication. If commTxPoolExceptional is received inhandover command (or RRCConnectionReconfiguration message), UE usescommTxPoolExceptional without sensing (i.e. randomly select resourcefrom resource pool) from the reception of handover command Alternatelysensing can be performed for commTxPoolExceptional wherein sensingperiod for commTxPoolExceptional can be smaller (pre-defined orsignaled) than normal sensing duration. UE continue to usecommTxPoolExceptional until the handover is completed i.e. until thetimer (i.e. T304, T304 is started by UE when handover command isreceived from source cell and stopped when handover to target cell issuccessfully completed) associated with handover is running. In otherwords if T304 is running, UE uses commTxPoolExceptional without sensingi.e. random selection.

FIG. 28 illustrates an eNB apparatus according to an embodiment of thepresent disclosure.

Referring to FIG. 28, the eNB 2800 includes a transceiver 2810, aprocessor 2820 and a memory 2830. Alternatively, the transceiver may beimplemented as a transmitter and a receiver, and each component may beimplemented through one or more processors. The transceiver can transmittransmission resource pool information to a UE and the memory can storetransmission resource pool information. The processor is configured todetermine transmission resource pool of the UE and control thetransceiver and the memory according to various embodiments of thepresent disclosure. A processor 2820 can include at plural processors.

FIG. 29 illustrates a UE apparatus according to an embodiment of thepresent disclosure.

Referring to FIG. 29, the UE 2900 includes a transceiver 2910, aprocessor 2920 and a memory 2930. Alternatively, the transceiver may beimplemented as a transmitter and a receiver, and each component may beimplemented through one or more processors. The transceiver can receivetransmission resource pool information from an eNB and transmitscheduling information and data for V2V/V2X communication usingresources in the transmission resource pool. The memory can storetransmission resource pool information. The processor is configured todetermine resources in the transmission resource pool randomly orperform sensing on the transmission resource pool and determineresources in the transmission resource pool based on the sensing resultsand control the transceiver and the memory according to variousembodiments of the present disclosure. A processor 2920 can include atplural processors.

The above-described various embodiments of the present disclosure andthe accompanying drawings have been provided only as specific examplesin order to assist in understanding the present disclosure and do notlimit the scope of the present disclosure. Accordingly, those skilled inthe art to which the present disclosure pertains will understand thatother change examples based on the technical idea of the presentdisclosure may be made without departing from the scope of the presentdisclosure.

While the present disclosure has been shown and described with referenceto various embodiments thereof, it will be understood by those skilledin the art that various changes in form and details may be made thereinwithout departing from the spirit and scope of the present disclosure asdefined by the appended claims and their equivalents.

What is claimed is:
 1. A method performed by a terminal in acommunication system, the method comprising: receiving, from a basestation, a radio resource control (RRC) message comprising informationon a normal resource pool; based on the terminal receiving informationon an exceptional resource pool and a sensing result on the normalresource pool being not available, randomly selecting a resource fromthe exceptional resource pool, wherein the resource from the exceptionalresource pool is for transmitting a scheduling assignment (SA) and datacorresponding to the SA to another terminal; and transmitting the SA andthe data based on the randomly selected resource from the exceptionalresource pool.
 2. The method of claim 1, further comprising: based onthe sensing result on the normal resource pool being available,selecting a resource from the normal resource pool based on the sensingresult; and transmitting an SA and data on the selected resource fromthe normal resource pool.
 3. The method of claim 1, wherein theexceptional resource pool is used for transmitting the SA and the datauntil a sensing is completed on the normal resource pool.
 4. The methodof claim 1, wherein the information on the exceptional resource pool isreceived by system information (SI).
 5. The method of claim 1, whereinthe information on the exceptional resource pool is received by the RRCmessage.
 6. The method of claim 1, wherein the information on the normalresource pool comprises commTxPoolNormalDedicated or commTxPoolNormal,and wherein the information on the exceptional resource pool comprisescommTxPoolExceptional.
 7. A method performed by a base station in acommunication system, the method comprising: transmitting, to aterminal, a radio resource control (RRC) message comprising informationon a normal resource pool; and transmitting, to the terminal,information on an exceptional resource pool by the RRC message or systeminformation (SI), wherein a resource randomly selected from theexceptional resource pool is used for transmitting a schedulingassignment (SA) and data corresponding to the SA to another terminaluntil a sensing result on the normal resource pool is available.
 8. Themethod of claim 7, wherein the information on the normal resource poolcomprises commTxPoolNormalDedicated or commTxPoolNormal, and wherein theinformation on the exceptional resource pool comprisescommTxPoolExceptional.
 9. A terminal in a communication system, theterminal comprising: a transceiver; and at least one processorconfigured to: receive, from a base station via the transceiver, a radioresource control (RRC) message comprising information on a normalresource pool, based on the terminal receiving information on anexceptional resource pool and a sensing result on the normal resourcepool being not available, randomly select a resource from theexceptional resource pool, wherein the resource from the exceptionalresource pool is for transmitting a scheduling assignment (SA) and datacorresponding to the SA to another terminal, and transmit, via thetransceiver, the SA and the data based on the randomly selected resourcefrom the exceptional resource pool.
 10. The terminal of claim 9, whereinthe at least one processor is further configured to: based on thesensing result on the normal resource pool being available, select aresource from the normal resource pool based on the sensing result, andtransmit an SA and data on the selected resource from the normalresource pool.
 11. The terminal of claim 9, wherein the exceptionalresource pool is used for transmitting the SA and the data until asensing is completed on the normal resource pool.
 12. The terminal ofclaim 9, wherein the information on the exceptional resource pool isreceived by system information (SI).
 13. The terminal of claim 9,wherein the information on the exceptional resource pool is received bythe RRC message.
 14. The terminal of claim 9, wherein the information onthe normal resource pool comprises commTxPoolNormalDedicated orcommTxPoolNormal, and wherein the information on the exceptionalresource pool comprises commTxPoolExceptional.
 15. A base station in acommunication system, the base station comprising: a transceiver; and acontroller configured to: transmit, to a terminal via the transceiver, aradio resource control (RRC) message comprising information on a normalresource pool, and transmit, to the terminal via the transceiver,information on an exceptional resource pool by the RRC message or systeminformation (SI), wherein a resource randomly selected from theexceptional resource pool is used for transmitting a schedulingassignment (SA) and data corresponding to the SA to another terminaluntil a sensing result on the normal resource pool is available.
 16. Thebase station of claim 15, wherein the information on the normal resourcepool comprises commTxPoolNormalDedicated or commTxPoolNormal, andwherein the information on the exceptional resource pool comprisescommTxPoolExceptional.
 17. The method of claim 1, wherein theinformation on the exceptional resource pool is included in interfrequency information list in an RRC connection reconfiguration message.18. The method of claim 1, wherein the information on the normalresource pool is included in inter frequency information list in an RRCconnection reconfiguration message.
 19. The method of claim 7, whereinthe information on the exceptional resource pool is included in interfrequency information list in the RRC message, and wherein the RRCmessage corresponds to RRC connection reconfiguration message.
 20. Themethod of claim 7, wherein the information on the normal resource poolis included in inter frequency information list in the RRC message, andwherein the RRC message corresponds to RRC connection reconfigurationmessage.
 21. The terminal of claim 9, wherein the information on theexceptional resource pool is included in inter frequency informationlist in an RRC connection reconfiguration message.
 22. The terminal ofclaim 9, wherein the information on the normal resource pool is includedin inter frequency information list in an RRC connection reconfigurationmessage.
 23. The base station of claim 15, wherein the information onthe exceptional resource pool is included in inter frequency informationlist in the RRC message, and wherein the RRC message corresponds to RRCconnection reconfiguration message.
 24. The base station of claim 15,wherein the information on the normal resource pool is included in interfrequency information list in the RRC message, and wherein the RRCmessage corresponds to RRC connection reconfiguration message.